Many different types of information may be transmitted from one point on a computer network to another. Such information is sometimes referred to as “content” which may include various forms or combinations of electronic information such as text, audio, and/or visual information (often referred to as multimedia content). One form of content transmission across a network is through a technique known as “streaming.” Using this streaming technique, a person at a remote computer terminal may request content over the Internet or other network which is subsequently “streamed” to the content requester. Employing one of several widely available media players such as Windows Media Player™, or RealOne Player™, the user may quickly and easily observe the streamed content at his or her computer terminal.
When a user requests a content stream directly from an information source, the response to the request is often handled by a server or other remote computer that sends a content stream directly to the requester. This method of sending an information stream from one point to another, in a more or less direct fashion, is called a “unicast” transmission in which one dedicated data stream is typically sent per request. Another way in which the server may respond to the request is by transmitting an information stream throughout the communication network without regard to whether a user downstream is interested the information being streamed. This method of sending information over a network is sometimes referred to as a “broadcast” transmission.
An alternative approach to unicast and broadcast transmission is called “multicasting.” Using this approach, a single stream of information is sent from a content server which is subsequently “divided” into additional identical content streams and provided to users.
Multicasting, unicast, and broadcast transmission all involve bandwidth issues that are of particular concern to network service providers.